The present invention relates generally to techniques for automatically arranging music performance information and more particularly to a technique for making a good-quality automatic arrangement (musical arrangement) with accent positions of an original music piece taken into consideration.
Japanese Patent Application Laid-open Publication No. 2005-202204 (hereinafter referred to as “Patent Literature 1”) discloses a technique in which a user selects a desired part (musical part) from MIDI-format automatic performance data of a plurality of parts (musical parts) of a given music piece and a musical score of a desired format is created for the user-selected part. According to a specific example disclosed in Patent Literature 1, the user selects a melody part, accompaniment data suitable for a melody of the selected melody part are automatically created, and then a musical score comprising the selected melody part and an accompaniment part based on the automatically-created accompaniment data is created. More specifically, as a way of automatically creating the accompaniment data suitable for the melody in the disclosed technique, a plurality of accompaniment patterns corresponding to different performance levels (i.e., levels of difficulty of performance) are prepared in advance, an accompaniment pattern that corresponds to a performance level selected by the user is selected from the prepared accompaniment patterns, and then accompaniment data are automatically created on the basis of the selected accompaniment pattern and with a chord progression in the melody taken into consideration.
It may be said that the automatic accompaniment data creation disclosed in Patent Literature 1 automatically makes an arrangement of the accompaniment on the basis of a given melody. However, the automatic accompaniment data creation disclosed in Patent Literature 1 is merely designed to change pitches of tones, constituting an existing accompaniment pattern (chord backing, arpeggio, or the like), in accordance with a chord progression of the melody; thus, it cannot make an accompaniment arrangement harmonious with a rhythmic element of the original music piece. Thus, because the accompaniment added by the automatic accompaniment is not harmonious with the rhythmic element of the original music piece, there would arise the inconvenience that accent positions originally possessed by the original music piece are canceled out. Further, if a performance of the accompaniment based on the accompaniment data automatically created as above is executed together with a melody performance of the original music piece, for example, on a keyboard musical instrument, the performance tends to become difficult due to disagreement or disharmony in accent position between the right hand (melody performance) and the left hand (accompaniment performance) of a human player.